+, $x=\dfrac{-1}{2}.\dfrac{4}{3}$
$=\dfrac{(-1).4}{2.3}$
$=\dfrac{-4}{6}$
$=\dfrac{-2}{3}$
+, $\dfrac{x}{5}=\dfrac{5}{6}.\dfrac{-30}{19}$
$⇔\dfrac{x}{5}=\dfrac{-25}{19}$
$⇔x=\dfrac{-125}{19}$
+, $\dfrac{x}{15}=\dfrac{3}{5}.\dfrac{-2}{3}$
$⇔\dfrac{x}{15}=\dfrac{-2}{5}$
$⇔x=-6$
+, $\dfrac{11}{8}.\dfrac{6}{13}=\dfrac{77}{x}$
$⇔\dfrac{77}{x}=\dfrac{33}{52}$
$⇔x=\dfrac{364}{3}$
+, $x+\dfrac{7}{8}=\dfrac{13}{12}.\dfrac{4}{5}$
$⇔x+\dfrac{7}{8}=\dfrac{13}{15}$
$⇔x=\dfrac{-1}{120}$
